A supply chain is generally used to refer to a system of organizations, people, technology, activities, information and resources involved in moving products (e.g., raw materials such as industrial gases) from one point (such as a manufacturer's facility) to another (such as a customer's distribution or manufacturing center). For example, a supply chain may be used to describe the production and delivery of industrial gases in bulk to tanks at a customer site. In such a supply chain, a producer may generate product using an air separation unit (ASU) to separate atmospheric air into gaseous components (e.g., oxygen gas (O2), nitrogen gas (N2), hydrogen gas (H2), Argon gas (Ar)), as well as produce mixtures of these molecular gases. Elements of this supply chain (i.e., the production, storage, and delivery of industrial gases) itself may be a component of other supply chains for the customers where the product is then delivered. That is, a customer may use the industrial gases in manufacturing or other production activities, resulting in the creation and distribution of products to other customers.
Gases refined using an ASU may be stored in tanks prior to being delivered to customers. For example, gases may be stored in tanks at the production site (or transported over a pipeline to tanks at a storage facility). From there, a delivery truck obtains product for bulk delivery to customers.
A producer/distributor of industrial gases typically faces a variety of transportation logistics and distribution problems in managing a bulk-delivery supply chain. Overall, the producer/distributor would like to use the resources of their distribution network in an optimal manner. For example, the producer/distributor would like to optimize bulk distribution, cylinder delivery and retrieval, production schedules, delivery schedules, etc.). Optimizing a supply chain for such a delivery and distribution network has proven to be a complex task. In particular, generating a delivery schedule that satisfies customer demand, minimizes global cost, and that is robust to outages in production proves to be a difficult challenge, as the number of combinatoric possibilities for creating a bulk-delivery schedule is very large. This fact makes it difficult for a producer/distributor to effectively determine a robust schedule for delivering products to a set of customers. At the same time, for even a moderately sized producer/distributor of industrial gases, creating a robust bulk delivery schedule can provide a substantial benefit.